In order to enhance chip processability in cutting, a throw-away tip is provided with a chip breaker such as a breaker groove and a breaker wall.
For example, Japanese Patent Laying-Open No. 4-217404 (PTD 1), Japanese Patent Laying-Open No. 4-217405 (PTD 2), and Japanese Patent Laying-Open No. 4-217406 (PTD 3) disclose defining a chip breaker in surface roughness to curl chips spirally.